MIT graduate engineering students working to aid doctors determined to solve difficult medical problems presented their prototypes of proposed medical devices at the March 4 Forum at Simches Research Center at Massachusetts General Hospital.

The students were part of a CIMIT-inspired program, the 2.996/6.971 Biomedical Devices Design Course, which links engineers with medical professionals. Moderator of this Forum was Hong Ma, PhD, postdoctoral associate, Department of Mechanical Engineering, MIT, and instructor of the 2.996/6.971 course.
 
The goal for the students is to deliver a working prototype and a journal-quality article in one semester. The course has been a great opportunity for clinicians to test novel ideas and stimulate new collaborations.

One prototype presented was the GRIT Chair Alarm. The Gesture Recognition Interactive Technology alarm was designed to improve wheelchair alarms for patients at risk of falling when they stand. This system responds with light and voice alarms that can encourage the patient to remain seated and/or make use of the system’s integrated nurse-call function. The team’s solution can be integrated into existing hospital WiFi network, sending messages to the nurse call system as well as providing the patient’s location. Team members included Lauren Kattany, RN, clinical nurse specialist at MGH, and students Heather Knight and Jae-Kyu Lee.

A second team presented the SmartPad, a device that displays a patient’s electrocardiogram (EKG) signal without adhesives or wires. Instead, sensors are bonded to a foam mat, on which the patient lies during an operation. The device displays an EKG waveform, which, while inferior to a cardiologist’s EKG, would be sufficient for the doctor to monitor the patient’s health. It is designed to obtain data without having to use multiple electrodes on the body, which can sometimes inhibit the success of clinician’s hands-on access to the patient. Team leader was Dr. Sheridan, who is chief, Burn Surgery Service, Shriners Hospital for Children; and co-director, Sumner Redstone Adult Burn Unit, MGH, and students Fred Chen, Pei-Lan Hsu, Brad Stronger, Henry Wu and Dr. Ma.

A third team produced a Hand-Held Endotracheal Tube Placement Sensor. This team has developed a hand-held ETT placement sensor, which is a portable device that allows a doctor or nurse to “see” the endotracheal tube’s position in the throat. Currently there are no convenient means of verifying the tube’s position in a patient’s throat. The device uses a two-dimensional array of Giant Magnetoresistance (GMR) sensors to localize the position of a tiny magnet embedded into the ETT. As the sensor is held over the sternal notch, the sensor unit measures a magnetic strength underneath the sensing area. An onboard microprocessor displays an intuitive color-coded map on an LCD screen.  The device is designed to fit into a hand or pocket, and run off an internal rechargeable lithium-polymer battery. An integrated wireless module allows the device to be adapted for continuous monitoring and automated notification of hospital staff if a potential problem is detected. Team members included Dr. Sheridan, and students Keith Durand, Byron Hsu, Brandon Pierquet and Warit Wichakool.

Several engineering students said they are now interested in seeking opportunities in the medical-device field as a result of taking the course.

Falls are a major problem in hospitals around the world, for they hurt patients and can cause costly injuries. Nurses are usually the people primarily responsible for preventing falls, but they are often asked to tend many patients while simultaneously performing a number of other tasks. Although getting out of bed helps a patient avoid many conditions such as deep vein thrombosis, skin breakdown, and functional decline, nurses are sometimes forced to limit a patient's mobility because they feel unable to ensure that patient's safety. Current devices used to prevent patients from getting up and attempting to walk around include bed alarms, clips, and restraints. Restraints are undesirable because they are uncomfortable and frightening for patients and because they can make a fall very dangerous. Bed alarms and clips have other drawbacks. They do not alert individual caregivers, they are only set off after a patient has gotten up, and they are prone to false alarms. A new device is needed that will alert individual nurses when a patient begins to get up, not after the fact.

To solve this problem, graduate students from MIT created a chair alarm based on gesture recognition interactive technology (GRIT). Their device is a pad that can be placed on existing chairs and that can communicate wirelessly with the hospital's existing WiFi network. It consists of pressure sensors on the seat and arms of the chair, and proximity sensors on the back of the chair. A microchip takes these inputs and uses an algorithm to figure out what the patient is doing (whether he or she leaning forward to get up, whether he or she is fidgeting, etc.). When the device recognizes a dangerous gesture, such as leaning forward while pressing on the arms of the chair, it wirelessly alerts the nurse's station, and it also communicates with the patient via a speaker, asking him or her to sit back down. Because it can differentiate amongst a number of behaviors, the device can respond in a tiered fashion and can give instructions to suit the situation. Unlike previous chair alarms, the GRIT alarm system recognizes behaviors that occur early in the process of getting up. Thus, it is can preemptively alert a nurse while simultaneously asking the patient to remain seated. The GRIT chair alarm is a nuanced tool that will help nurses prevent falls and that may be applicable to other situations in which patient monitoring is required.

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